Instead of knocking on every door or on those where it appeared someone was home, though, Imhoff scrolled through her phone and called out the addresses of only certain voters.

Smith, a Republican Party field director, and Imhoff, a volunteer, were helping implement a new GOP strategy being rolled out nationwide that aims to identify undecided voters in certain neighborhoods and win them over by tailoring questions and responses to each voter’s particular situation.

The party hopes to improve its canvassing efficiency, ensure its backers are registered to vote and seize the technological advantage that Democrats first widely used to help propel Barack Obama to victory in 2008 and get him re-elected president four years later.

Actually knowing which side is doing a better job on get out the vote work is impossible — at least until Election Day.

“Ground game operations are one of the most secretive and black magic elements of all campaigns,” said Marquette University pollster Charles Franklin.

This much is known — Republicans in Wisconsin and elsewhere have been using new data and analytics tools to improve voter outreach, fundraising and campaign tactics.

Democrats, too, are fighting to maintain the edge they developed leading into the presidential election as they face the challenge of mobilizing their side in an off-year election.

“The things we’re doing now are going to make the difference on Nov. 4,” said Joe Fadness, executive director of the Wisconsin Republican Party. “There’s no doubt about it.”

Both Fadness and Wisconsin Democratic Party Chairman Mike Tate say a solid ground game operation could bring between 2 percent and 5 percent of voters to the polls, which could be enough to sway a close election like this year’s governor’s race is expected to be.

The most recent Marquette University Law School poll, which came out in May, had the race between Walker and Democrat Mary Burke, a former state Commerce secretary and Trek Bicycle Corp. executive, as a dead heat.

Democrats have done well in presidential years in Wisconsin, having carried the state every election since 1988. But in the last midterm in 2010, Walker won by 6 percentage points. That same year, which was huge for the GOP nationwide, Republicans also took control of the state Senate and Assembly and ousted Democratic incumbent Sen. Russ Feingold.

Walker won the recall election in June 2012 by 7 points. But that fall, Obama carried the state by 7 points and liberal Democrat Tammy Baldwin was elected to the U.S. Senate over former Republican Gov. Tommy Thompson.

Almost immediately after that, Wisconsin Republicans started preparing for this fall and the Walker re-election, Fadness said. That has put them far ahead of Democrats this election cycle, he said.

“(Democrats are) putting the plane together while they’re flying the plane,” Fadness said. “We understand now campaigning is 24-7, 365.”

Tate rejected the notion that the Republicans will overtake the Democrats’ ground game operation.

“Our ground game will absolutely outperform the Republicans and the reason for that is they are still trying to catch up to technology we’ve been perfecting for several cycles in a row,” Tate said. “I’m very confident in our ability at a very micro level to identify voters we need to get to the polls.”